1. Field of the Invention
This invention relates to a novel indolecarboxylic ester trimer. Compositions containing said trimer as a main ingredient are usable as an electrochemical cell, a chemical sensor, a display element, an organic EL material, anon-linear material, etc.
2. Description of the Prior Art
As trimeric derivatives of indole, 6-nitroindole trimers and 5-cyanoindole trimers have hitherto been known. These trimeric derivatives have been used as electrochemical cells using proton as electric charge carrier thereof (cf. Japanese Patent Kokai 2002-93419). On the other hand, WO 02/32903 refers to indolecarboxylic acid trimer derivatives such as indole-4-carboxylic acid trimer, indole-5-carboxylic acid trimer, indole-6-carboxylic acid trimer, indole-7-carboxylic acid trimer, and the like. However, the above-mentioned WO 02/32903 gives no concrete description of indolecarboxylic ester trimers with reference to working example.
As have been mentioned above, 6-nitroindole trimer, 5-cyanoindole trimer and indole-5-carboxylic acid trimer are known as prior arts. However, it has been desired to develop a new indole trimer derivative different from the above-mentioned known ones which can give an electrode active material sufficient in electromotive force and capacity, and excellent in the cycle characteristics.